Pregnancy rate after emergency contraception with single-dose oral levonorgestrel in Japanese women

Abstract

Aim: To evaluate the pregnancy rate in Japanese women treated with levonorgestrel for emergency contraception.

Methods: This retrospective record-based medical study included 1000 women who visited our clinic for emergency contraceptive treatment with 1.5 mg single-dose oral levonorgestrel, followed by 50 μg hormonal oral contraceptive from May 2011 to December 2017. The outcomes of the emergency contraceptive treatment were recorded at a follow-up visit, and descriptive statistics were obtained.

Results: The number of women treated with levonorgestrel at the clinic increased from 2011 to 2015, but there was no subsequent increase thereafter. Most women were in their 20s (57.4%), followed by their 30s (19.3%) and teens (18.3%). Of the 1000 women treated with levonorgestrel, 659 were followed up. Among the 659 women with follow-up data, 16 were pregnant (2.4%), of whom 11 underwent abortions, three had miscarriages, and two delivered at term. The timing of unprotected sexual intercourse relative to the estimated ovulation date among the pregnant women ranged from -3 to 23 days. The most commonly used contraceptive method before the emergency contraceptive visit was condoms (89.3%, 887/993). No new safety concerns were identified throughout the study period.

Conclusion: The pregnancy rate after levonorgestrel treatment in Japanese women was low, and similar to that reported in previous studies. Information on contraceptive methods and emergency contraception with levonorgestrel needs to be better disseminated among women of childbearing age.

Keywords: emergency contraceptive; hormonal oral contraceptive; levonorgestrel; pregnancy rate; sex education.